Vibration damper composition

ABSTRACT

The present invention has for its object to provide a damping material which, despite a high damping capacity at and around room temperature, has a small temperature dependence of rigidity at and around room temperature and a damping material having hot-melt processability and a good balance between damping capacity and temperature dependence of rigidity at and around room temperature. 
     This invention provides a damper material composition
         wherein the ratio of the storage modulus (G′) value at 0° C. to the corresponding value at 40° C. as found by the measurement of dynamic viscoelasticity in the shear mode, namely (G′ 0° C. /G′ 40° C. ), is not greater than 15   and the loss tangent (tan δ) value as found by said measurement is not smaller than 0.4 at 0° C. to 40° C.

RELATED APPLICATIONS

This application is a nationalization of PCT application PCT/JP01/02972filed Apr. 5, 2001. This application claims priority from the PCTapplication and Japan Application Serial No. 2000-103962 filed Apr. 5,2000 and Japan Application Serial No. 2001-027319 filed Feb. 2, 2001.

TECHNICAL FIELD

The present invention relates to a damper material composition for useas a damper (viscoelastic damper) which absorbs the impact displacementand vibrations of framework structural members in the field ofarchitecture and to a damper and a vibtration-damping double-sidedadhesive tape, in which the composition is employed.

BACKGROUND ART

In the field of architecture, we are witnessing the development ofvibration dampers for absorbing the vibrations caused by earthquakes,typhoons, etc. to thereby incorporate a very efficient damping mechanismin buildings. Damping materials for vibration dampers are required to behigh in damping capacity in order that the impact displacement andvibrations of the framework structural members of buildings may beabsorbed and, at the same time, small in the temperature dependence ofrigidity at and around room temperature in consideration ofenvironmental conditions.

While materials of high molecular weight generally show high dampingcapacities in the neighborhood of glass transition temperature (Tg),this Tg region is the temperature region where such a high molecularmaterial undergoes a transition from a highly rigid glass-like state toa sparingly rigid rubbery state and is also a region of high temperaturedependence of rigidity. Therefore, it is usual that damping materialsfor general use are used at and around the glass transition temperatureso as to let them express high damping capacities [Vibration DampingTechnology, The Japan Society of Mechanical Engineers (ed.) Yokendo, p.75].

In the architectural field, where changes in atmospheric temperaturefrom summer months to winter months and vice versa and regionaldifferences in atmospheric temperature, it is essential to avoid usingdamping materials having a large temperature dependence of rigidity.However, high damping capacities can hardly be expected at temperaturesoutside the glass transition temperature region, where the temperaturedependence of rigidity is small. Thus, a small temperature dependence ofrigidity and a large damping capacity are conflicting characteristics inpolymer materials and usually it is extremely difficult to reconcilethese two parameters.

Ordinary rubber materials have a certain degree of damping capacity atand around room temperature but if an attempt is made to increase thedamping capacity, the rigidity will be sacrificed, with the result that,as a practical problem, the down-sizing of dampers are difficult.Moreover, these materials are hardly capable of providing a high dampingcapacity enough to use for dampers.

As damping rubbers exhibiting high damping capacities at and around roomtemperature, oil-modified norbornene rubbers and high-vinylstyrene-isoprene block copolymers and their hydrogenated versions(HYBLAR™), among others, are commercially available. These dampingrubbers generally have glass transition points (Tg) at and around roomtemperature. Such materials have high damping capacities at and aroundroom temperature but show large changes in elastic modulus around Tg sothat the temperature dependence of rigidity at and around roomtemperature is very large, making them hardly applicable to dampers.

As damping materials for viscoelastic dampers in the architecturalfield, polyurethane compounds and polyurethane/asphalt compositions areknown (Japanese Kokai Publication Hei-10-330451). However, all suchmaterials remain to be further improved in regard of the balance betweendamping capacity and temperature-dependence of rigidity at and aroundroom temperature. Particularly because the Tg of such a composition isdesigned to be not over 0° C. in order to minimize the temperaturedependence of rigidity at and around room temperature, the dampingcapacity in the temperature region of about 20 to 40° C. is unduly low.

On the other hand, it is disclosed in WO 93/14135 and Japanese KokaiPublication Hei-7-137194 that damping materials may be obtained fromstyrene-isobutylene block copolymers but all that is disclosed there isthat only general-purpose damping materials may be obtained and neitherdisclosure includes teachings on applications demanding specialcharacteristics such as those required of viscoelastic dampers for usein the field of architecture. Moreover, in the materials specificallydescribed as examples in the above publications, the glass transitiontemperature is invariably below −15° C. so that the temperaturedependence of rigidity is small at and around room temperature. However,the damping capacities of these materials at and around room temperatureare too low for them to use as damping materials.

In addition, the damper material composition for vibration dampersmaterials must have a rigidity of the order retaining its shape and adeformability capable of with standing large seismic vibrations due toan earthquake.

The technology of fabricating vibration dampers from such dampingmaterials includes the method comprising laminating a damper sheet withsteel plates using an adhesive and the hot-melt method comprisingmelt-molding the damping material. The laminating method using anadhesive is suitable for the processing of damping materials in thesheet form but does not easily lend itself to the fabrication of othershapes. Therefore, the damper material composition for vibration damperspreferably has self-adhesive properties. On the other hand, the hot-meltmethod comprises merely pouring a molten viscoelastic material intomolds so that the material can be easily processed into a variety ofshaped products, with the additional advantage that the processing costis low. From these points of view, the damping materials for vibrationdampers preferably have hot-melt properties.

SUMMARY OF THE INVENTION

The present invention, developed in the above state of the art, has forits object to provide not only a damping material which, despite a highdamping capacity at and around room temperature, has a small temperaturedependence of rigidity at and around room temperature, as well asself-adhesive properties and good deformability, but also a damper and adouble-sided self-adhesive tape having a vibration damping function,both of which are comprised of said damping material.

It is a further object of the invention to provide not only a dampingmaterial having hot-melt processability and a good balance betweendamping capacity and temperature dependence of rigidity at and aroundroom temperature but also a damper and a double-sided self-adhesive tapehaving a vibration damping function, both of which are comprised of saiddamping material.

The first aspect of the present invention, therefore, is concerned witha damper material composition

wherein the ratio of the storage modulus (G′) value at 0° C. to thecorresponding value at 40° C. as found by the measurement of dynamicviscoelasticity in the shear mode, namely (G′_(0° C.)/G′_(40° C.)), isnot greater than 15

and the loss tangent (tan δ) value as found by said measurement is notsmaller than 0.4 at 0° C. to 40° C.

The first aspect of the present invention is specifically concerned witha damper material composition

which comprises a block copolymer (A) comprising a polymer block (a) anda polymer block (b) and terminating in said polymer block (b),

said polymer block (a) being comprised of an aromatic vinyl compound asa constituent monomer,

and said polymer block (b) being comprised of isobutylene as aconstituent monomer.

The second aspect of the present invention is concerned with a dampermaterial composition comprising a diblock copolymer (A′) comprising apolymer block (a′) and a polymer block (b),

said polymer block (a′) being comprised of an aromatic vinyl compound asa constituent monomer and having a number average molecular weight ofnot more than 10,000,

and said polymer block (b) being comprised of isobutylene as aconstituent monomer.

The third aspect of the present invention is concerned with a vibrationdamper having structure of a combination of said damper materialcomposition with steel sheet or pipe.

The fourth aspect of the present invention is concerned with a dampingdouble-sided self-adhesive tape comprising said damper materialcomposition as molded in the form of a tape.

Hereinafter, the invention is described in detail.

DISCLOSURE OF THE INVENTION

The damper material composition according to the first aspect of thepresent invention is preferably a composition such that the ratio of thestorage modulus (G′) value at 0° C. to the corresponding value at 40° C.as found by a dynamic viscoelasticity measurement in the shear mode,namely (G′_(0° C.)/G′_(40° C.)), is not more than 15 and that the losstangent (tan δ) value found by said measurement is not less than 0.4 at0° C. to 40° C.

The dynamic viscoelasticity in the shear mode can be measured inaccordance with JIS K-6394 (Testing methods for dynamic properties ofvulcanized rubber and thermoplastic rubber). The frequency to be usedshould be 0.1 to 5 Hz. This range corresponds to the frequency ofvibrations of buildings in an earthquake or a typhoon. The storagemodulus (G′) and loss tangent (tan δ) values found by such a dynamicviscoelasticity measurement in the shear mode correspond to theequivalent rigidity (Keq) and equivalent damping factor (heq) parametersused in the field of architecture and the following relation is known tohold: G′=Keq, tan δ=2·heq. In the above relation, G′ represents therigidity of a damping material. The larger the value of G′ is, thehigher is the rigidity. On the other hand, tan δ represents the dampingcapacity of a damping material, and the larger the value is, the greateris the damping capacity. As mentioned above, when a damping material isto be used as a viscoelastic damper, it must have a large dampingcapacity and a small temperature dependence of rigidity at and aroundroom temperature.

The measurement of dynamic viscoelasticity in the shear mode isperformed using a specimen with an S/D value (unit: mm) [where S standsfor shear area (unit: mm²) and D stands for thickness (unit: mm)] of notless than 20. For example, when 2 specimens each measuring 5 mm×6 mm×2mm (thickness) are used, the S/D value is 30 mm. When the S/D value isless than 20, the influence of deformation other than pure sheardeformation tends to appear.

In the damper material composition according to the first aspect of theinvention, the ratio of the G′ value at 0° C. (G′_(0° C.)) to thecorresponding value at 40° C. (G′_(40° C.)), namely(G′_(0° C.)/G′_(40° C.)), is preferably not more than 15, morepreferably not more than 12, and still more preferably not more than 10.Furthermore, in the damper material composition according to the firstaspect of the invention, the tan δ value at 0° C. to 40° C. ispreferably not less than 0.4, more preferably not less than 0.5, stillmore preferably not less than 0.7.

The damper material composition according to the first aspect of theinvention preferably comprises a block copolymer (A) comprising apolymer block (a) comprised of an aromatic vinyl compound as aconstituent monomer and a polymer block (b) comprised of isobutylene asa constituent monomer and terminating in said polymer block (b). Thepolymer block (A) is preferably a diblock copolymer of the polymer block(a)—polymer block (b) structure because of a balance between dampingcapacity and temperature dependence of rigidity at and around roomtemperature.

The inventors of the present invention discovered that a polymer block(b)—terminated block copolymer (A) shows a peculiar glass transitionbehavior and arrived at the present invention.

A block copolymer not terminating in a polymer block (b), for example atriblock copolymer of the (a)-(b)-(a) structure has a glass transitionpoint corresponding to the polymer block (a) and a glass transitionpoint corresponding to the polymer block (b). This kind of behavior isobserved generally in block copolymers each comprising a combination ofpolymer blocks having a tendency toward phase separation and is aphenomenon well known to those skilled in the art.

However, the inventors found after an intensive investigation that ablock copolymer (A) terminating in the polymer block (b) has a thirdglass transition point intermediate between the glass transition pointcorresponding to the polymer block (a) and the glass transition pointcorresponding to the polymer block (b). Therefore, the block copolymer(A) terminating in the polymer block (b) shows a peak tan δ valuecorresponding to said third glass transition point in the rubber regionabove the glass transition point of the polymer block (b). As aconsequence, despite the fact that in the usual rubber region, thetemperature dependence of rigidity (G′) is small but the dampingperformance (tan δ) is also low, the damper material composition of theinvention shows a high damping capacity in this region where thetemperature dependence of rigidity is small.

The block copolymer (A) which can be used in the first aspect of theinvention is not particularly restricted as far as it is a blockcopolymer comprising polymer block (a) and polymer block (b) andterminating in the polymer block (b) and can be any of block, diblock,triblock and multi-block copolymers having a linear, branched, stellaror other structure. Thus, the block copolymer (A) satisfying the desiredviscoelastic characteristics, physical properties such as maximum straincoefficient and shear strength, and processability can be selected. Byusing a block copolymer comprising said polymer block (b) comprised ofisobutylene as a constituent monomer in at least one terminal positionand at least one said polymer block (a) comprised of an aromatic vinylcompound as a constituent monomer, the damping capacity in thetemperature region of 20 to 40° C. can be augmented without increasingthe temperature dependence of rigidity at and around room temperature.The reason is that when the polymer block (b) comprised of isobutyleneas a constituent monomer exists at the molecular terminus, said polymerblock (b) is increased in motility to form a highly intermingled phasewith the polymer block (a) comprised of an aromatic vinyl compound as aconstituent monomer, with the result that an intermediate Tg appears denovo between the Tg of the polymer block (b) comprised of isobutylene asa constituent monomer and the Tg of the polymer block (a) comprised ofan aromatic vinyl compound as a constituent monomer.

While the polymer block (a) is a polymer block comprised of an aromaticvinyl compound as a constituent monomer, the aromatic vinyl compound isnot particularly restricted as far as it has an aromatic ring and acarbon-carbon double bond conducive to cationic polymerization. Asspecific examples, there can be mentioned styrene, o-, m- orp-methylstyrene, α-methylstyrene, β-methylstyrene, 2,6-dimethylstyrene,2,4-dimethylstyrene, α-methyl-o-methylstyrene, α-methyl-m-methylstyrene,α-methyl-p-methylstyrene, β-methyl-o-methylstyrene,β-methyl-m-methylstyrene, β-methyl-p-methylstyrene,2,4,6-trimethylstyrene, α-methyl-2,6-dimethylstyrene,α-methyl-2,4-dimethylstyrene, β-methyl-2,6-dimethylstyrene,β-methyl-2,4-dimethylstyrene, o-, m- or p-chlorostyrene,2,6-dichlorostyrene, 2,4-dichlorostyrene, α-chloro-o-chlorostyrene,α-chloro-m-chlorostyrene, α-chloro-p-chlorostyrene,β-chloro-o-chlorostyrene, β-chloro-m-chlorostyrene,β-chloro-p-chlorostyrene, 2,4,6-trichlorostyrene,α-chloro-2,6-dichlorostyrene, α-chloro-2,4-dichlorostyrene,β-chloro-2,6-dichlorostyrene, β-chloro-2,4-dichlorostyrene, o-, m- orp-t-butylstyrene, o-, m- or p-methoxystyrene, o-, m- orp-chloromethylstyrene, o-, m- or p-bromomethylstyrene, silyl-substitutedstyrene derivatives, indene, vinylnaphthalene, and so on. These may beused singly or in a combination of two or more species. The preferred,among them, is at least one selected from the group consisting ofstyrene, p-methylstyrene, α-methylstyrene, p-chlorostyrene,p-t-butylstyrene, p-methoxystyrene, p-chloromethylstyrene,p-bromomethylstyrene, silyl-substituted styrene derivatives and indene.The more preferred is at least one selected from the group consisting ofstyrene, α-methylstyrene, p-methylstyrene and indene. From cost pointsof view, styrene, α-methylstyrene or a mixture thereof is particularlypreferred.

The polymer block (a) may additionally contain a monomer or monomersother than said aromatic vinyl compound. When it contains any monomerother than the aromatic vinyl compound, the aromatic vinyl compoundpreferably accounts for not less than 60 weight %, more preferably notless than 80 weight %, of the total weight of the polymer block (a). Themonomer or monomers other than the aromatic vinyl compound in thepolymer block (a) is not particularly restricted inasmuch as they aremonomers capable of undergoing cationic polymerization with the aromaticvinyl compound, thus including such monomers as isobutylene, aliphaticolefins, dienes, vinyl ethers, β-pinene and so on. These may be usedsingly or in a combination of two or more species.

The polymer block (a) preferably has a number average molecular weightof not more than 10,000 as will be described later herein.

The polymer block (b) as a component of the block copolymer (A)according to the first aspect of the invention is a polymer blockcomprised of isobutylene as a constituent monomer.

While the polymer block (b) is comprised of isobutylene, it mayoptionally contain a monomer or monomers other than isobutylene. When itadditionally contains such a monomer or monomers other than isobutylene,the proportion of isobutylene in the polymer block (b) is preferably notless than 60 weight %, more preferably not less than 80 weight %. Themonomer other than isobutylene in the polymer block (b), that can beused, is not particularly restricted as far as it is capable ofundergoing cationic polymerization with isobutylene, thus including saidaromatic vinyl compounds, aliphatic olefins, dienes, vinyl ethers andβ-pinene, among other monomers. These may be used singly or in acombination of two or more species.

In the context of the invention, the aliphatic olefin includes ethylene,propylene, 1-butene, 2-methyl-1-butene, 3-methyl-1-butene, pentene,hexene, cyclohexene, 4-methyl-1-pentene, vinylcyclohexane, octene andnorbornene. These may be used singly or in a combination of two or morespecies. The preferred, among them, are 1-butene, 2-methyl-1-butene,3-methyl-1-butene, pentene, hexene, cyclohexene, 4-methyl-1-pentene,vinylcyclohexane, octene and norbornene.

In the context of the invention, the diene includes butadiene, isoprene,hexadiene, cyclopentadiene, cyclohexadiene, dicyclopentadiene,divinylbenzene and ethylidenenorbornene. These may be used singly or ina combination of two or more species.

Also in the context of the invention, the vinyl ether includes methylvinyl ether, ethyl vinyl ether, (n-, iso)propyl vinyl ether, (n-, sec,tert-, iso-)butyl vinyl ether, methyl propenyl ether and ethyl propenylether. These may be used singly or in a combination of two or morespecies.

In the block copolymer (A), the relative proportions of the polymerblock (a) comprised of an aromatic vinyl compound as a constituentmonomer and the polymer block (b) comprised of isobutylene as aconstituent monomer are not particularly restricted but, in terms of thebalance between physical state and processability, the polymer block(a)/polymer block (b) ratio is preferably 2/98 to 60/40 by weight, morepreferably 5/95 to 40/60 by weight.

The number average molecular weight of the block copolymer (A) is notparticularly restricted, either, but in terms of the balance betweenphysical state and processability, it is preferably within the range of3,000 to 1,000,000, more preferably 5,000 to 500,000. When the numberaverage molecular weight of the block copolymer (A) is below theabove-defined range, the intrinsic physical properties of thecomposition are not fully expressed. On the other hand, exceeding theabove range results in poor processability.

The preferred structure of block copolymer (A), in terms of the physicalstate and processability of the composition, is at least one selectedfrom the group consisting of a diblock copolymer of the polymer block(a)—polymer block (b) structure, a triblock copolymer of the polymerblock (b)—polymer block (a)—polymer block (b) structure, and a stellatecopolymer comprising a core of said polymer block (a) and arms of saidpolymer block (b).

From the standpoint of the ease of production, a diblock copolymer ofthe polymer block (a)—polymer block (b) structure is particularlypreferred.

For the purpose of improving the adhesion of the damper materialcomposition of the invention to steel sheets or pipes, for instance,copolymers having various functional groups terminally or intermediatelyof the molecular chain can also be employed as the block copolymer (A).As such functional groups, there may be mentioned epoxy, hydroxyl,amino, alkylamino, alkoxy and other ether groups, carboxyl,alkoxycarbonyl, acyloxy and other ester groups, carbamoyl,alkylcarbamoyl, acylamino and other amido groups, maleic anhydride andother acid anhydride groups, silyl, allyl, vinyl and other groups. Theblock copolymer (A) may have only one of these functional groups or twoor more of them. The functional groups which are preferred in terms ofthe balance of physical properties, for instance, are epoxy, amino,ether, ester, amido, silyl, allyl and vinyl groups.

The method of producing the block copolymer (A) is not particularlyrestricted but includes various known polymerization techniques.However, in order that a block copolymer of controlled structure may beproduced, it is preferred to copolymerize a monomer component comprisingisobutylene as a predominant monomer and a monomer component comprisingan aromatic vinyl compound as a predominant monomer in the presence of acompound represented by the following general formula (I).(CR¹R²X)_(n)R³  (I)wherein X represents a substituent group selected from the groupconsisting of a halogen atom, an alkoxy group containing 1 to 6 carbonatoms and an acyloxy group containing 1 to 6 carbon atoms. R¹ and R²each represents a hydrogen atom or a univalent hydrocarbon groupcontaining 1 to 6 carbon atoms. R¹ and R² may be the same or different.Moreover, R¹ and R², when plural, may respectively be the same group ordifferent groups. R³ represents an n-valent aromatic hydrocarbon groupor an n-valent aliphatic hydrocarbon group. n represents a naturalnumber of 1 to 6.

The halogen atom mentioned above includes chlorine, fluorine, bromineand iodine. The alkoxy group containing 1 to 6 carbon atoms is notparticularly restricted but may for example be methoxy, ethoxy or n- orisopropoxy. The acyloxy group containing 1 to 6 carbon atoms is notparticularly restricted but may for example be acetyloxy orpropionyloxy. The hydrocarbon group containing 1 to 6 carbon atoms isnot particularly restricted but may for example be methyl, ethyl, or n-or isopropyl.

To synthesize a diblock copolymer of the polymer block (a)—polymer block(b) structure, a compound of the above general formula (I) wherein n=1can be used. To synthesize a triblock copolymer of the polymer block(b)—polymer block (a)—polymer block (b) structure, a compound of theabove general formula (I) wherein n=2 can be used. Further, tosynthesize a stellate polymer having a core of polymer block (a) andarms of polymer block (b), a compound of the above general formula (I)wherein n=3 to 6 can be used.

The compound represented by the above general formula (I) acts as aninitiator, being suspected to form a carbocation in the presence of aLewis acid or the like to provide an initiation site for cationicpolymerization. As examples of the compound of general formula (I) whichcan be used in the present invention, the following compounds, amongothers, can be mentioned.

-   (1-Chloro-1-methylethyl)benzene: C₆H₅C(CH₃)₂Cl,-   2-Methoxy-2-phenylpropane: C₆H₅C(CH₃)₂OCH₃,-   2-Chloro-2,4,4-trimethylpropane: (CH₃)₃CCH₂C(CH₃)₂Cl,-   1,4-Bis(1-chloro-1-methylethyl)benzene:-   1,4-Cl(CH₃)₂CC₆H₄C(CH₃)₂Cl,-   1,3-Bis(1-chloro-1-methylethyl)benzene:-   1,3-Cl(CH₃)₂CC₆H₄C(CH₃)₂Cl,-   1,3,5-Tris(1-chloro-1-methylethyl)benzene:-   1,3,5-(ClC(CH₃)₂)₃C₆H₃,-   1,3-Bis(1-chloro-1-methylethyl)-5-(tert-butyl)benzene:-   1,3-(C(CH₃)₂Cl)₂-5-(C(CH₃)₃)C₆H₃.

Particularly preferred, among these, are(1-chloro-1-methylethyl)benzene: C₆H₅C(CH₃)₂Cl,bis(1-chloro-1-methylethyl)benzene: Cl(CH₃)₂CC₆H₄C(CH₃)₂Cl andtris(1-chloro-1-methylethyl)benzene: (ClC(CH₃)₂)₃C₆H₃.

Incidentally, (1-chloro-1-methylethyl)benzene is also known asα-chloroisopropylbenzene, 2-chloro-2-propylbenzene or cumyl chloride;bis(1-chloro-1-methylethyl)benzene is also known asbis(α-chloroisopropyl)benzene, bis(2-chloro-2-propyl)benzene or dicumylchloride; and tris(1-chloro-1-methylethyl)benzene is also known astris(α-chloroisopropyl)benzene, tris(2-chloro-2-propyl)benzene ortricumyl chloride.

The above polymerization reaction can be conducted in the presence of aLewis catalyst. The Lewis catalyst need only be a compound that can beused for cationic polymerization, thus including metal halides, such asTiCl₄, TiBr₄, BCl₃, BF₃, BF₃.OEt₂, SnCl₄, SbCl₅, SbF₅, WCl₆, TaCl₅,VCl₅, FeCl₃, ZnBr₂, AlCl₃, AlBr₃, etc., and organometal halides such asEt₂AlCl, EtAlCl₂, etc., to mention but a few preferred examples. Inconsideration of catalytic activity and commercial availability, TiCl₄,BCl₃ and SnCl₄ are preferred.

The amount of use of the Lewis catalyst is not particularly restrictedbut can be selected in consideration of the polymerizing properties andconcentration of the monomers used, among other variables.

In conducting the above polymerization reaction, an electron donorcomponent may be caused to be present concomitantly as necessary. Theelectron donor component is considered to be effective in stabilizingthe polymer growth-associated carbocation in cationic polymerization,and by adding such an electron donor, there can be obtained a polymerhaving a controlled narrow molecular weight distribution. The electrondonor component is not particularly restricted but includes pyridines,amines, amides, sulfoxides, esters, and metal compounds having an oxygenatom bound to the metal atom, among others.

Where necessary, the above polymerization reaction may be carried out inan organic solvent. The organic solvent is not particularly restrictedas far as it does not substantially inhibit the cationic polymerization.As examples, there can be mentioned halogenated hydrocarbons such asmethyl chloride, dichloromethane, chloroform, ethyl chloride,dichloroethane, n-propyl chloride, n-butyl chloride and chlorobenzene;benzene, toluene, xylene, and alkylbenzenes such as ethylbenzene,propylbenzene and butylbenzene; straight-chain aliphatic hydrocarbonssuch as ethane, propane, butane, pentane, hexane, heptane, octane,nonane and decane; branched-chain aliphatic hydrocarbons such as2-methylpropane, 2-methylbutane, 2,3,3-trimethylpentane and2,2,5-trimethylhexane; cyclic aliphatic hydrocarbons such ascyclohexane, methylcyclohexane and ethylcyclohexane; paraffin oilprepared by hydrogenation and purification of a petroleum distillate.

These solvents can be used singly or in a combination of two or morespecies taking into consideration the polymerization characteristics ofthe constituent monomers of the block copolymer (A) and the solubilityof the product polymer, among other factors.

The amount of use of said solvent is selected so as to give a polymerconcentration of 1 to 50 wt. %, preferably 3 to 35 wt. %, inconsideration of the viscosity of the resulting polymer solution and theease of heat removal.

In conducting the polymerization reaction on a commercial scale, therespective components are admixed under cooling, for example at atemperature not below −100° C. but below 0° C. To strike a balancebetween the cost of energy and the stability of polymerization, thepreferred temperature range is −80° C. to −30° C.

The above polymerization reaction can be conducted batchwise (batch orsemi-batch method) or on a continuous mode in which each componentnecessary for polymerization is continuously fed to a reactor.

The method of producing a stellate polymer having said polymer block (a)as the core and said polymer block (b) as the arm component is notparticularly restricted but includes the method which comprisescopolymerizing a monomer component predominantly composed of an aromaticvinyl compound with a monomer component predominantly composed ofisobutylene in the presence of a compound having 3 or more cationicpolymerization initiation sites and the method which comprisescopolymerizing a monomer component predominantly composed of isobutylenewith a monomer component predominantly composed of an aromatic vinylcompound to prepare a diblock copolymer and, then, coupling (jointing)said diblock copolymer with a polyfunctional compound as a coupling(jointing) agent.

As the polyfunctional compound mentioned just above, a compound having 3or more reaction sites (functional groups) for coupling can be used.Also usable is a compound having 2 reaction sites per mole and capableof polymerizing or reacting to form a polymer have 3 or more reactionsites (functional groups).

The polyfunctional compound mentioned above includes divinyl aromaticcompounds such as 1,3-divinylbenzene, 1,4-divinylbenzene,1,2-diisopropenylbenzene, 1,3-diisopropenylbenzene,1,4-diisopropenylbenzene, 1,3-divinylnaphthalene,1,8-divinylnaphthalene, 2,4-divinylbiphenyl,1,2-divinyl-3,4-dimethylbenzene, 1,3-divinyl-4,5,8-tributylnaphthalene,2,2′-divinyl-4-ethyl-4′-propylbiphenyl, etc.; trivinyl aromaticcompounds such as 1,2,4-trivinylbenzene, 1,3,5-trivinylnaphthalene,3,5,4′-trivinylbiphenyl, 1,5,6-trivinyl-3,7-diethylnaphthalene, etc.;diepoxides such as cyclohexane diepoxide, 1,4-pentane diepoxide,1,5-hexane diepoxide, etc.; diketones such as 2,4-hexanedione,2,5-hexanedione, 2,6-heptanedione, etc.; dialdehydes such as1,4-butanedial, 1,5-pentanedial, 1,6-hexanedial, etc.; siloxanecompounds and calixarenes. These may be used singly or in a combinationof 2 or more species.

Among these, from the standpoint of reactivity, physical properties ofthe product stellate polymer, etc., divinyl aromatic compounds can beused with advantage, and it is particularly preferable to use at leastone species selected from the group consisting of 1,3-divinylbenzene,1,4-divinylbenzene, 1,3-diisopropenylbenzene and1,4-diisopropenylbenzene. These compounds are generally availablecommercially as mixtures with, for example, ethylvinylbenzene and thelike and as far as such mixtures are predominantly composed of saiddivinyl aromatic compound or compounds, they can be used as they are or,if desired, may be purified to higher purity and put to use.

The block copolymer (A) content of the damper material compositionaccording to the first aspect of the present invention should vary withthe other components used in combination and cannot be specified ingeneral terms but is preferably not less than 20 weight %, morepreferably not less than 30 weight %. Below this formulating amount, thebalance between damping capacity and temperature dependence of rigidityat and around room temperature tends to be adversely affected.

The damper material composition according to the first aspect of thepresent invention may contain any other optional components in additionto said block copolymer (A) comprising a polymer block (a) comprised ofan aromatic vinyl compound as a constituent monomer and a polymer block(b) comprised of isobutylene as a constituent monomer and terminating insaid polymer block (b). As such other optional components, there can bementioned thermoplastic polymers such as a thermoplastic resin (C) and athermoplastic elastomer (D), a tackifying resin, a plasticizer and afiller, among others.

The thermoplastic resin (C) is added for the purpose of improving therigidity and deformability of the damper material composition.

The thermoplastic resin (C) includes ethylene-propylene copolymer,ethylene-butene copolymer, ethylene-hexene copolymer, ethylene-octenecopolymer, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylatecopolymer, high-density polyethylene, low-density polyethylene, linearlow-density polyethylene, polypropylene, natural rubber, diene polymerrubber, olefin polymer rubber, acrylic rubber and urethane rubber, amongothers. The diene polymer rubber includes isoprene rubber, butadienerubber, 1,2-polybutadiene, styrene-butadiene rubber, chloroprene rubber,nitrile rubber and so on. The olefin polymer rubber includesisobutylene-isoprene copolymer (commonly known as butyl rubber),halogenated butyl rubber, ethylene-propylene-diene rubber and so on.

The preferred, among these, in consideration of the good compatibilitywith the block copolymer (A), small influence on temperature dependencyof rigidity, damping capacity and other dynamic characteristics, andease of control of rigidity and deformability, are ethylenic copolymerssuch as ethylene-propylene copolymer, ethylene-butene copolymer,ethylene-hexene copolymer, ethylene-octene copolymer, ethylene-vinylacetate copolymer, ethylene-ethyl acrylate copolymer, high-densitypolyethylene, low-density polyethylene, linear low-density polyethylene,etc. and isobutylene-isoprene copolymer (butyl rubber).

When the thermoplastic resin (C) is formulated, the amount of its use isnot particularly restricted but may usually be 1 to 1000 weight partsrelative to 100 weight parts of the block copolymer (A). Fromcomposition performance points of view, the range of 1 to 100 weightparts is preferred.

The thermoplastic elastomer (D) (in the context of the invention, thethermoplastic elastomer does not include the block copolymer (A)) isused for improving the cohesive force of the damper material compositionand improving the rigidity and deformability. The thermoplasticelastomer (D) includes styrenic thermoplastic elastomers, olefinicthermoplastic elastomers, vinyl chloride thermoplastic elastomers,urethane thermoplastic elastomers, polyester thermoplastic elastomersand polyamide thermoplastic elastomers, among others. Preferred, amongthese, from the standpoint of compatibility with the block copolymer (A)are styrenic thermoplastic elastomers.

Particularly preferred, among such styrenic thermoplastic elastomers, interms of industrial availability is a triblock copolymer comprising (apolymer block comprised of an aromatic vinyl compound as a constituentmonomer)—(a polymer block comprised of a conjugated diene as aconstituent monomer and optionally hydrogenated)—(a polymer blockcomprised of an aromatic vinyl compound as a constituent monomer) and atriblock copolymer comprising (a polymer block comprised of an aromaticvinyl compound as a constituent monomer)—(a polymer block comprised ofisobutylene as a constituent monomer)—(a polymer block comprised of anaromatic vinyl compound as a constituent monomer). In this connection,the polymer block comprised of a conjugated diene as a constituentmonomer and optionally hydrogenated includes conjugated diene polymerblocks (e.g. polybutadiene block, polyisoprene block, etc.), partiallyhydrogenated conjugated diene polymer blocks, and completelyhydrogenated conjugated diene polymer blocks (e.g. ethylene-butylenecopolymer block, ethylene-propylene copolymer block, etc.), amongothers.

As the aromatic vinyl compound mentioned above, it is preferable to useat least one monomer selected from the group consisting of styrene,α-methylstyrene, p-methylstyrene and indene, and from the standpoint ofcost, styrene, α-methylstyrene or a mixture thereof is particularlypreferred. The conjugated diene mentioned above includes butadiene andisoprene, among others. These may be used singly or in a combination oftwo species.

When the thermoplastic elastomer (D) is formulated, the amount of itsuse is not particularly restricted but may generally be 1 to 1000 weightparts relative to 100 weight parts of the block copolymer (A), with therange of 1 to 100 weight parts being preferred from the standpoint ofperformance of the composition.

The tackifying resin is a low-molecular-weight resin having a numberaverage molecular weight of 300 to 3,000 and a softening point of 60 to150° C. as measured by the ring-and-ball method defined in JIS K-2207,thus including rosins, rosin derivatives, polyterpene resins,aromatic-modified terpene resins and hydrogenation products thereof,terpene-phenol resins, chroman-indene resins, aliphatic petroleumresins, alicyclic petroleum resins and hydrogenation products thereof,aromatic petroleum resin and hydrogenation products thereof,aroma-to-aliphatic copolymer petroleum resins, dicyclopentadienepetroleum resins and hydrogenation products thereof, styrene andsubstituted styrene, among other low-molecular-weight polymers.

The tackifying resin mentioned above is effective in shifting the Tg ofthe polymer block (b) comprised of isobutylene as a constituent monomertoward the higher end of the temperature scale. To attain this shift, itis recommendable to formulate a tackifying resin which is compatiblewith the polymer block comprised of isobutylene as a constituent monomerand constituting the block copolymer (A). As tackifying resins of thiskind, there can be used alicyclic petroleum resins and hydrogenationproducts thereof, aliphatic petroleum resins, hydrogenated aromaticpetroleum resins and polyterpene resins, to mention but a few preferredexamples.

Among tackifying resins within the same category, one having a highersoftening point is more effective in shifting the Tg of the polymerblock (b) comprised of isobutylene as a constituent monomer andconstituting the block copolymer (A) toward the higher end of thetemperature scale. Therefore, when it is desirable to reduce theformulating amount of the tackifying resin, a resin with a highersoftening point can be selected, while a resin with a lower softeningpoint can be judiciously chosen when the formulating amount of thetackifying resin is to be increased.

The formulating amount of the tackifying resin, when used, is notparticularly restricted but is generally 1 to 1000 weight parts and,from the standpoint of performance of the composition, is preferably 1to 100 weight parts, relative to 100 weight parts of the block polymer(A).

The plasticizer may be any of petroleum process oils such as paraffinprocess oil, naphthene process oil, aromatic process oil, etc., dibasicacid dialkyl esters such as diethyl phthalate, dioctyl phthalate,dibutyl adipate, etc., and low-molecular-weight liquid polymers such asliquid polybutene, liquid polyisoprene and so on. Such a plasticizer asabove is effective in shifting the Tg of the polymer block comprised ofisobutylene as a constituent monomer toward the lower end of thetemperature scale, and for such purposes, it is preferable to formulatea plasticizer compatible with the polymer block (b) comprised ofisobutylene as a constituent monomer and constituting the blockcopolymer (A). Thus, paraffin process oil or liquid polybutene, forinstance, can be used with advantage.

The formulating amount of the plasticizer, when used, is notparticularly restricted but is generally 1 to 1000 weight parts and,from the standpoint of performance of the composition, is preferably 1to 100 weight parts, based on 100 weight parts of the block copolymer(A).

As examples of the filler, there can be mentioned powdered fillers suchas, for example, mica, carbon black, silica, calcium carbonate, talc,graphite, stainless steel and aluminum powders; and fibrous fillers suchas glass fiber and metal fiber. Among these, mica is particularlypreferred because it contributes to improvement in damping capacity.Furthermore, when a metal powder, such as stainless steel powder andaluminum powder, a metal fiber, or an electrically conductive powder,such as carbon black and graphite, is formulated, spot welding is madefeasible.

As other formulating additives, there can be mentioned stabilizers suchas triphenyl phosphite, hindered phenol, dibutyltin maleate, etc.;lubricants such as polyethylene wax, polypropylene wax, montanic acidwax, etc.; flame retardants such as triphenyl phosphate, tricresylphosphate, decabromobiphenyl, decabromobiphenyl ether, antimonytrioxide, etc.; and pigments such as titanium oxide, zinc sulfide, zincoxide and so on.

The preferred damper material composition according to the first aspectof the present invention is a composition comprising the block copolymer(A) as well as at least one of the thermoplastic resin (C) andthermoplastic elastomer (D) and in a weight ratio of 100/0 to 30/70based on 100 weight parts of the mixture, and containing 5 to 200 weightparts of the tackifying resin and/or plasticizer. The more preferred isa composition comprising the block copolymer (A) as well as at least oneof the thermoplastic resin (C) and thermoplastic elastomer (D) in aweight ratio of 95/5 to 40/60 based on 100 weight parts of the mixture,and containing 10 to 150 weight parts of the tackifying resin and/orplasticizer. Particularly preferred is a composition comprising theblock copolymer (A) as well as at least one of the thermoplastic resin(C) and thermoplastic elastomer (D) in a weight ratio of 90/10 to 50/50based on 100 weight parts of the mixture, and containing 5 to 100 weightparts of the tackifying resin and/or plasticizer.

When at least one of the thermoplastic resin (C) and thermoplasticelastomer (D) is not formulated, the cohesive force of the dampermaterial composition is so small that the composition tends to bedeficient in deformability. On the other hand, if the addition amount istoo high, the cohesive force of the damper material composition willbecome so large as to cause a relative decrease in the adhesion tosteel, thus leading to insufficient adhesion.

The tackifying resin and plasticizer are formulated for the purpose ofadjusting the glass transition temperature and controlling thetemperature dependence of rigidity and damping capacity of the dampermaterial composition. However, there are cases in which the rigidity isdecreased with an increasing addition amount. Therefore, if the additionamount is too high, a rigidity sufficient to retain the shape may not bemaintained.

The second aspect of the present invention is directed to a dampermaterial composition comprising a diblock copolymer (A′) comprising apolymer block (a′) and a polymer block (b),

said polymer block (a′) being comprised of an aromatic vinyl compound asa constituent monomer and having a number average molecular weight ofnot more than 10,000

and said polymer block (b) being comprised of isobutylene as aconstituent monomer.

The polymer block (a′) is a polymer block comprised of an aromatic vinylcompound as a constituent monomer and having a number average molecularweight of not more than 10,000. As this requirement relating to numberaverage molecular weight is satisfied, a damping material havinghot-melt processability (showing a low melt viscosity under heating at ahigh temperature) can be obtained. When the number average molecularweight is higher than 10,000, the polymer block does not melt even whenheated to a high temperature so that the composition does not lenditself well to hot-melt processing, although the damper may have a goodbalance between damping capacity and temperature dependence of rigidityat and around room temperature. To improve hot-melt processability, thetackifier and/or plasticizer may be formulated in an increased amount tothereby lower the melt viscosity at high temperature but such a practiceis not recommendable because the balance between damping capacity andtemperature dependence of rigidity at and around room temperature wouldthen be adversely affected.

The number average molecular weight of the polymer block (a′) ispreferably not more than 9,000, more preferably not more than 8,000.Also, it is preferably not less than 1,000, more preferably not lessthan 2,000. When the number average molecular weight of the polymerblock (a′) is too low, the balance between damping capacity andtemperature dependence of rigidity at and around room temperature tendsto be adversely affected.

The procedure for calculation of the number average molecular weight ofthe polymer block (a′) is dependent on the method for production(polymerization) of the diblock copolymer (A′). Thus, when the copolymeris synthesized by polymerizing a monomer component containing anaromatic vinyl compound in the first place and, then, furtherpolymerizing a monomer component containing isobutylene, the numberaverage molecular weight of the polymer available on polymerization ofsaid monomer component containing an aromatic vinyl compound is used. Onthe other hand, when the copolymer (A′) is synthesized by polymerizingthe isobutylene-containing monomer component in the first place and,then, further polymerizing said monomer component containing an aromaticvinyl compound, the number average molecular weight of polymer block(a′) is the value calculated by means of the formula: (number averagemolecular weight of the end-product copolymer)—(the number averagemolecular weight of the polymer available on polymerization of theisobutylene-containing monomer component). Furthermore, when themolecular weight distribution of the end-product copolymer issufficiently small, the computation formula: (number average molecularweight of the end-product copolymer)×(styrene content (weight %) ofdiblock copolymer (A′))/100 may be employed.

It should be understood that, as used in this specification, the term“number average molecular weight” is the value measured by gelpermeation chromatography and expressed in polystyrene equivalent.

The constituent monomer component of the polymer block (a′) may be thesame as that mentioned for polymer block (a) in the block copolymer (A).

The polymer block (b) of the diblock copolymer (A′) according to thesecond aspect of the invention may be the same as the polymer block (b)described hereinbefore. Its number average molecular weight is notparticularly restricted but preferably such that the number averagemolecular weight of the whole diblock copolymer (A′) will assume asuitable value.

The ratio of the polymer block (a′) comprised of an aromatic vinylcompound as a constituent monomer to the polymer block (b) comprised ofisobutylene as a constituent monomer in the diblock copolymer (A′) isnot particularly restricted but, in terms of the balance betweenphysical state and processability, the weight ratio of polymer block(a′)/polymer block (b) is preferably 5/95 to 40/60, more preferably10/90 to 40/60.

The number average molecular weight of the diblock copolymer (A′) is notparticularly restricted but, from the standpoint of physical propertiesand processability, is preferably 3,000 to 200,000, more preferably5,000 to 50,000. When the number average molecular weight is less thanthe above range, the composition cannot fully express its physicalcharacteristics. On the other hand, when it exceeds the above range,processability is poor.

For the purpose of improving the adhesion of the composition accordingto the second aspect of the invention to steel sheets and pipes, forinstance, diblock copolymers having various functional groups internallyor terminally of the molecular chain can be used as said diblockcopolymer (A′). The functional groups may be the same as those mentionedhereinbefore.

The method of producing the diblock copolymer (A′) may be the same asthe technology described hereinbefore for the production of the diblockcopolymer (A).

The diblock copolymer (A′) content of the damper material compositionaccording to the second aspect of the invention should vary withdifferent components used concomitantly and cannot be stated in generalterms but is preferably not less than 20 weight %, more preferably notless than 30 weight %. Below the above range, the balance betweendamping capacity and temperature dependence of rigidity at and aroundroom temperature tends to be adversely affected.

The damper material composition of this invention need only be acomposition which comprises a diblock copolymer (A′) comprising saidpolymer block (a′) comprised of an aromatic vinyl compound as aconstituent monomer and having a number average molecular weight of notmore than 10,000 and said polymer block (b) comprised of isobutylene asa constituent monomer and may contain any other optional component otherthan the diblock copolymer (A′). Such optional components includethermoplastic polymers such as thermoplastic elastomers andthermoplastic resins, tackifying resins, plasticizers, fillers andstabilizers which have already been mentioned and the formulatingamounts thereof may also be the same as those mentioned hereinbefore.

Addition of a thermoplastic elastomer, in particular, is effective inenhancing the cohesive force and increasing the breaking strain of thediblock copolymer (A′). Addition of a thermoplastic resin is effectivein increasing the rigidity of the diblock copolymer (A′). Addition of atackifying resin and/or a plasticizer is effective in improving thedamping capacity and hot-melt processability of the diblock copolymer(A′). Further, the damping capacity and rigidity can be modulated byadding said filler and the thermal stability during processing andlong-term durability can be improved by adding said stabilizer.

For application to a vibration damper, the damper material compositionis required to have a high damping capacity and a small temperaturedependence of rigidity at and around room temperature. Therefore, thedamper material composition according to the second aspect of theinvention is preferably such that the ratio of the storage modulus (G′)value at 10° C. to the corresponding value at 30° C. as found by adynamic viscoelasticity measurement in the shear mode, namely(G′_(10° C.)/G′_(30° C.)), is not more than 5 and the loss tangent (tanδ) value found by said measurement is not less than 0.4 at 10° C. to 30°C.

Thus, in the damper material composition of this invention, the ratio(G′_(10° C.)/G′_(30° C.)) of the G′ value at 10° C. (G′_(10° C.)) to theG′ value at 30° C. (G′_(30° C.)) is preferably not more than 5, morepreferably not more than 4, still more preferably not more than 2.Furthermore, in the damper material composition of the invention, thetan δ value at 10° C. to 30° C. is preferably not less than 0.4, morepreferably not less than 0.5, still more preferably not less than 0.7.

The method of producing the damper material composition of the inventionis not particularly restricted but includes a method comprising mixingthe components mechanically by means of a mixing roll, a Banbury mixer,a kneader, a melting furnace equipped with a stirrer, or a single-screwor twin-screw extruding machine. This mixing procedure may optionally becarried out under heating. An alternative method comprises pouring thecomponents in a suitable solvent, stirring the mixture to give ahomogeneous solution of the composition and distilling off the solvent.Where necessary, the damper material composition can be molded andcrosslinked by means of a press, for instance.

The damper material composition of the invention can be used incombination with steel sheets or pipes to provide architectural dampers.The kind of steel sheet or pipe which can be used for such dampers isnot restricted but includes general-purpose structural steel sheets,cold rolled steel sheets, carbon steel sheets, stainless steel sheetsand low-alloyed steel sheets, among others. The structure of a vibrationdamper may for example be a laminate structure comprising at least onelayer of the damper material composition of the invention and the samenumber plus one steel sheets as alternately laminated or a laminatestructure comprising at least one layer of the damper materialcomposition of the invention and the same number plus one steel pipes assimilarly laminated in a concentric manner.

In these cases, the damper material composition and steel sheet or pipemay be bonded together with an adhesive or without the aid of anadhesive.

Thickness of the damping material of the vibration damper can beselected according to the shearing force and deformation volume requiredfor the damper. Said thickness is generally within the range of 3 mm to20 mm. When the thickness is smaller than 3 mm, the damper cannot dealwith a large deformation due to an earthquake and the like to cause thefailure thereof. When the thickness is larger than 20 mm, the rigidityand shearing force of the damper tend to be too small.

The damping material can be molded by standard extruders, press-molders,hot-roller and the like. Molded products in the form of a sheet or tapemay be adhered with steel sheets or pipes. For example, when extrudersare used for molding, the screw temperature may be 80 to 200° C. and thedie temperature may be 50 to 150° C. Furthermore, the vibration moldersmay have a conventional shape, for example, those in the shape ofdiagonal brace, those in the shape of puncheon and those in the shape ofwall.

When the damper material composition has good hot-melt processability,it is possible to use a technique which comprises interposing the dampermaterial composition between steel sheets or pipes and heating the wholein an electric furnace, for instance, to cause the composition to meltand flow. An alternative technique comprises pouring the damper materialcomposition, previously molten, into the clearance between steel sheetsor pipes to fill up the clearance and bond them together. The meltingmay be effected generally within the temperature range of 150 to 300° C.

Furthermore, because the damper material composition of the inventionhas adhesive properties, it can be molded into a tape for use as adouble-sided self-adhesive tape having a damping function. As such adouble-sided self-adhesive tape having a vibration damping function isset between steel sheets, between wood members, or between a wood memberand a gypsum board, for instance, both sides of the tape stick to therespective adherends and, in this mode of use, the damper materialcomposition may undergo shear deformation in response to the vibrationscaused by a wind or an earthquake, thus insuring a vibration dampingeffect in an expedient manner.

The size of the self-adhesive tape may usually be 2 cm to 10 cm in widthand 0.3 mm to 3.0 mm in thickness. Formation of the tape can be carriedout with a standard extruder using a screw temperature of 80 to 200° C.and a die temperature of 50 to 150° C.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view showing a small-sized viscoelastic dampercomprising 2 damper material composition layers and 3 steel sheets aslaminated in an alternate manner and used in the measurement of dampingperformance of the viscoelastic damper.

FIG. 2 shows hysteresis loops showing the load-displacement relationshiprepresenting the damping performance of the viscoelastic damperfabricated in Example 9.

FIG. 3 shows hysteresis loops showing the load-displacement relationshiprepresenting the damping performance of the viscoelastic damperfabricated in Example 20.

DESCRIPTION OF LEGENDS

-   1: Surface-treated steel sheet-   2: Damping material

BEST MODE FOR CARRYING OUT THE INVENTION

The following examples illustrate the present invention in furtherdetail. It is to be understood that the invention is by no meansdelimited by these examples but can be judiciously modified withoutdeparting from its spirit and principles herein disclosed.

PRODUCTION EXAMPLE 1 Production of a Diblock Copolymer Comprising aPolystyrene Block and a Polyisobutylene Block

A 2 L reactor equipped with a stirrer was charged with 589 mL ofmethylcyclohexane (dried with molecular sieves in advance), 613 mL ofn-butyl chloride (dried with molecular sieves in advance) and 0.550 g ofcumyl chloride. After the reactor was cooled to −70° C., 0.35 mL ofα-picoline (2-methylpyridine) and 179 mL of isobutylene were added.Then, 9.4 mL of titanium tetrachloride was added and the polymerizationwas thus started. The reaction was carried out at −70° C. with constantstirring for 2.0 hours. To this reaction mixture was added 59 mL ofstyrene, and the reaction was further continued for 60 minutes, at theend of which time it was stopped by adding a large quantity of methanol.The solvent was removed from the reaction mixture and the polymer wasdissolved in toluene and washed with 2 portions of water. The washedtoluene solution was poured in methanol to precipitate the polymer,which was then dried in vacuo at 60° C. for 24 hours to give a diblockcopolymer (hereinafter referred to briefly as SIB-1).

The diblock copolymer thus obtained had a number average molecularweight (Mn) of 48,000 and a molecular weight distribution (Mw/Mn) of1.12. The number average molecular weight and molecular weightdistribution values were determined using Wasters 510 GPC system(solvent: chloroform, flow rate 1 mL/min). The molecular weight wasexpressed in polystyrene equivalent (the same applies hereinafter).

PRODUCTION EXAMPLE 2 Production of a Triblock Copolymer Comprising aPolystyrene Block, a Polyisobutylene Block and a Polystyrene Block

A 2 L reactor equipped with a stirrer was charged with 570 mL ofmethylcyclohexane (dried with molecular sieves in advance), 590 mL ofn-butyl chloride (dried with molecular sieves in advance) and 0.400 g ofdicumyl chloride. After the reactor was cooled to −70° C., 0.34 mL ofα-picoline (2-methylpyridine) and 174 mL of isobutylene were added.Then, 10.3 mL of titanium tetrachloride was added and the polymerizationwas thus started. The reaction was carried out at −70° C. with constantstirring for 2.0 hours. To this reaction mixture was added 58 mL ofstyrene, and the reaction was further continued for 60 minutes, at theend of which time it was stopped by adding a large quantity of methanol.The solvent was removed from the reaction mixture and the polymer wasdissolved in toluene and washed with 2 portions of water. The washedtoluene solution was poured in methanol to precipitate the polymer,which was then dried in vacuo at 60° C. for 24 hours to give a triblockcopolymer (hereinafter referred to briefly as SIBS-1).

The triblock copolymer thus obtained had a number average molecularweight of 98,000 and a molecular weight distribution value of 1.15.

EXAMPLES 1 TO 8 AND COMPARATIVE EXAMPLES 1 TO 7

The block copolymer (A) (SIB-1 prepared in Production Example 1), athermoplastic elastomer, a thermoplastic resin, a tackifying resin, anda plasticizer were kneaded together according to the formulas indicatedin Table 1 using a Labo-Plastomill (manufactured by Toyo PrecisionMachinery) set at 170° C. for 15 minutes to manufacture rubbercompositions. The rubber compositions were respectively press-molded at170° C. to prepare sheets. The moldability was excellent. From eachsheet, specimens measuring 5 mm×6 mm×1.7 mm were cut out.

(Measurement of Dynamic Viscoelasticity)

Using 2 specimens, the dynamic viscoelasticity of each composition wasmeasured at a frequency of 0.5 Hz and a shear strain of 0.05% inaccordance with JIS K-6394. As the measuring instrument, the dynamicviscoelasticity meter DVA-200 (manufactured by IT Metric Control) wasused. With regard to storage modulus (G′), the ratio of the value of G′at 0° C. (G′_(0° C.)) to the value of G′ at 40° C. (G′_(40° C.)), namely(G′_(0° C.)/G′_(40° C.)), and the ratio of the value of G′ at 10° C.(G′_(10° C.)) to the value of G′ at 30° C. (G′_(30° C.)), namely(G′_(10° C.)/G′_(30° C.)), were calculated. Moreover, with regard toloss tangent (tan δ), the values at 0° C., 10° C., 20° C., 30° C. and40° C. (tan δ_(10° C.), tan δ_(20° C.), tan δ_(30° C.), tan δ_(40° C.))were read.

(Evaluation of Vibration-Damping Performance)

The temperature dependence of rigidity as well as the dampingperformance at and around room temperature were rated according to thefollowing 3-grade evaluation schedule.

[Evaluation Schedule]

-   ◯: Good-   □: Usable as architectural viscoelastic damper-   X: Not usable as architectural viscoelastic damper    (Evaluation of Adhesion and Deformability)

From a sheet of the test damper material composition, a specimenmeasuring 25 mm×25 mm×2 mm thick was cut out and bonded as sandwichedbetween two 25 mm×100 mm×5 mm thick general-purpose structural steelsheets (SS400 (JIS G-3101)) sandblasted in advance for surface treatmentto fabricate a shear test specimen. When the damper material compositionwas self-adhesive, the sheet was sandwiched and melt-bonded at 150° C.by means of a hot press. When the damper material composition was notself-adhesive, steel sheets were coated with the adhesive Chemlock487A/B(product of Lord Far East Incorporated) and after 1 hour of drying atroom temperature, the sheet were bonded. In this case, to accelerate thecuring of the adhesive applied, the assembly was heated in an oven at100° C. for 10 minutes and left sitting at room temperature for 24hours.

The specimen thus prepared was pulled in the shear direction at a speedof 300 mm/min using Autograph AG-10TB (Shimadzu Corporation). Theadhesion was evaluated according to whether the damper materialcomposition sheet and steel sheet are peeled apart across the interfaceor the damper material composition sheet was destroyed. In the event ofinterfacial separation, the product cannot be used as an architecturaldamper because it will be subjected to a large force in an earthquake.

In the case of destruction of the sheet, the maximum strain up tofailure was measured to evaluate the deformability.

In Table 1, “Fusion” means melt-bonding and “Adhesive” means bondingwith the aid of an adhesive. Further, “Material” means the failure ofthe damping material and “Interface” means peeling across the interfacebetween the damper sheet and steel sheet.

The results are shown in Table 1.

TABLE 1 Example 1 2 3 4 5 6 7 8 Formulation, Block copolymer (A): partsby SIB-1 100 80 80 80 80 80 80 80 weight Thermoplastic elastomer: SIBS-1— 20 20 — — — — — SEPS — — — 20 20 — — — VS1 — — — — — — — — HSV3 — — —— — — — — SEBS — — — — — — — — Thermoplastic resin: ECC — — — — — 20 20— EVA — — — — — — — 20 Tackifying resin: P-100 30 30 — 30 50 30 50 30P-140 — — — — — — — — Plasticizer: PW380 — — 30 — 40 — 40 — 300H — — — —— — — — Filler: SC-60 — — — — — — — — Performance Storage modulus ratio2.4 2.5 2.2 2.1 1.4 2.9 2.7 3.1 evaluation (G′_(10° C.)/G′_(30° C.))Storage modulus ratio 7.4 7.4 4.1 5.2 2.2 4.3 9.0 11.8(G′_(0° C.)/G′_(40° C.)) Temp. dependence of ◯ ◯ ◯ ◯ ◯ ◯ ◯ Δ rigidityLoss tangent (0° C.) 1.22 1.22 0.50 0.92 0.99 0.98 1.21 1.12 (10° C.)0.93 0.97 0.58 0.73 0.59 0.89 0.92 1.04 (20° C.) 0.77 0.75 0.68 0.600.52 0.74 0.80 0.85 (30° C.) 0.73 0.68 0.70 0.56 0.55 0.67 0.90 0.75(40° C.) 0.80 0.68 0.63 0.60 0.71 0.69 1.05 0.75 Damping performance ◯ ◯Δ Δ Δ ◯ ◯ ◯ Method of bonding Melt- Melt- Melt- Melt- Melt- Melt- Melt-Melt- bond- bond- bond- bond- bond- bond- bond- bond- ing ing ing inging ing ing ing Adhesion (type of failure) Mate- Mate- Mate- Mate- Mate-Mate- Mate- Mate- rial rial rial rial rial rial rial rial Deformability(%) 90 580 550 580 980 190 180 170 (destruction strain) ComparativeExample 1 2 3 4 5 6 7 Formulation, Block copolymer (A): parts by SIB-1 —— — — — — — weight Thermoplastic elastomer: SIBS-1 100 100 100 100 — — —SEPS — — — — — — — VS1 — — — — 100 — — HSV3 — — — — — 100 — SEBS — — — —— — 100 Thermoplastic resin: ECC — — — — — — — EVA — — — — — — —Tackifying resin: P-100 — — 25 — — — — P-140 — — — 50 — — — Plasticizer:PW380 — — — — — — — 300H — 15 — — — — — Filler: SC-60 — 50 — — — — —Performance Storage modulus ratio 1.2 1.3 1.6 6.2 39.8 1.8 1.1evaluation (G′_(10° C.)/G′_(30° C.)) Storage modulus ratio 1.4 1.6 2.634.5 65.6 5.9 1.3 (G′_(0° C.)/G′_(40° C.)) Temp. dependence of ◯ ◯ ◯ X X◯ ◯ rigidity Loss tangent (0° C.) 0.31 0.43 0.90 0.46 0.20 1.36 0.08(10° C.) 0.21 0.29 0.59 0.51 0.31 0.69 0.06 (20° C.) 0.17 0.20 0.41 0.791.37 0.34 0.05 (30° C.) 0.15 0.16 0.31 0.95 0.66 0.20 0.04 (40° C.) 0.140.17 0.25 1.03 0.32 0.14 0.04 Damping performance X X X ◯ X X X Methodof bonding Adhe- Adhe- Adhe- Adhe- Adhe- Adhe- Adhe- sive sive sive sivesive sive sive Adhesion (type of failure) Inter- Inter- Inter- Inter-Inter- Inter- Inter- face face face face face face face Deformability(%) — — — — — — — (destruction strain)

Particulars of the thermoplastic elastomer, thermoplastic resin,tackifying resin, plasticizer and filler mentioned in Table 1 are asfollows.

-   Thermoplastic elastomer: SEPS (styrene-ethylene/propylene-styrene    triblock copolymer [SEPTON 2007, product of Kuraray Co.]-   Thermoplastic elastomer: VS1 (high-vinyl styrene-isoprene block    copolymer, HYBLAR VS-1, styrene content 20% [product of Kuraray Co.]-   Thermoplastic elastomer: HVS3 (hydrogenated high-vinyl    styrene-isoprene block copolymer, HYBLAR HVS-3, styrene content 20%    [product of Kuraray Co.]-   Thermoplastic elastomer: SEBS (hydrogenated styrene-butadiene block    copolymer, CRAYTON G-1650, styrene content 29% [product of Shell    Japan Co.]-   Thermoplastic resin: EOC (ethylene-octene copolymer (ENGAGE 8150,    product of Dow)-   Thermoplastic resin: EVA (ethylene-vinyl acetate copolymer (EV260,    product of Mitsui-DuPont)-   Tackifying resin: P-100 (hydrogenated C9 alicyclic petroleum resin,    ARCON P-100, softening point 100° C., molecular weight 610 (product    of Arakawa Chemical Industry)-   Tackifying resin: P-140 (hydrogenated C9 alicyclic petroleum resin,    ARCON P-140, softening point 140° C., molecular weight 860 (product    of Arakawa Chemical Industry)-   Plasticizer: PW-380 (paraffinic oil, Diana Process Oil PW-380,    viscosity 380 cSt (40° C.), density 0.8769 g/cm³, pour point −15° C.    (product of Idemitsu Kosan)-   Plasticizer: 300H (polybutene oil, Idemitsu Polybutene 300H,    viscosity 32,000 cSt (40° C.), density 0.900 g/cm³, pour point 0° C.    (product of Idemitsu Petrochemical)-   Filler: SC-60 (flaky graphite SC-60 (product of Nakagoshi Graphite)

All the compositions according to Examples 1 to 8 not only had tan δvalues as high as not less than 0.4 within the range of 0° C. to 40° C.but also (G′_(0° C.)/G′_(40° C.)) ratios as small as not more than 15 sothat they had a good balance between damping capacity and temperaturedependence of rigidity at and around room temperature and can,therefore, be used with advantage as damping materials for architecturalviscoelastic dampers. Such effects are attributable to the markedimprovements in tan δ at temperatures not below 20° C., particularly at30° C. to 40° C.

In Examples 4 and 5 where SEPS was used in lieu of the SIBS-1 used inExamples 2 and 3, the balance between tan δ and G′ was superior ascompared with Examples 2 and 3. In particular, improvements in the(G′_(0° C.)/G′_(40° C.)) ratio were remarkable. In Examples 6 and 7, EOCwas used in lieu of the SIBS-1 in Examples 2 and 3, and EVA was used inExample 8. In these formulations, too, improvements were obtained in tanδ at temperatures not below 20° C., particularly at 30° C. and 40° C.Further, in Example 8 where EVA was used, a tendency toward improvedadhesion between the damper material composition and the steel sheet wasobserved.

The damper material compositions according to Examples 1 to 8 invariablyhad self-adhesive properties and could be melt-bonded to steel sheetswithout the aid of an adhesive. Moreover, the resulting bond at aninterface between the steel sheet and damper material composition wasvery satisfactory and the type of failure was invariably the failure ofthe damping material. Furthermore, the compositions according toExamples 2 to 8 wherein the thermoplastic resin and thermoplasticelastomer were added to the damper material composition of Example 1showed a tendency toward improved deformability.

On the other hand, Comparative Example 1 in which only theisobutylene-based block copolymer described specifically in WO 93/14135and Japanese Kokai Publication Hei-7-137194 was used as the dampingmaterial and Comparative Example 2 in which the isobutylene-based blockcopolymer/polybutene/flaky graphite=100/15/50 (by weight) compositiondescribed specifically in WO 93/14135 was used as the damping materialboth showed low tan δ values at and around room temperature and did nothave the characteristics required of damping materials for architecturalviscoelastic damper use. Comparative Example 3 in which theisobutylene-based block copolymer/ARCON P-100=100/25 (by weight)composition described specifically in Japanese Kokai PublicationHei-7-137194 was used as the damping material showed high tan δ valuesover 0° C. to 10° C. but unduly low tan δ values at temperatures notbelow 20° C. so that it cannot be used as a damping composition forarchitectural viscoelastic damper use. Comparative Example 4 in whichthe kind and formulating amount of tackifying resin were optimized toimprove tan δ values at and around room temperature, the tan δ values attemperatures not below 20° C. were improved but the temperaturedependence of rigidity was increased. Thus, according to the prior arttechnology, it is impossible to strike a balance between dampingcapacity and temperature dependence of rigidity at and around roomtemperature.

Furthermore, the conventional compositions have no self-adhesiveproperties and, even when bonded to a steel sheet with the aid of anadhesive, the laminate shows an interfacial failure and cannot be usedas an architectural vibration damper. Thus, when an architectural damperundergoes a shear deformation in an earthquake, a force commensuratewith the amount of deformation is generated but if an interfacialfailure takes place when the deformation has become large, the stressfrom the damper is abruptly relieved so that a large load is imposed onthe building.

It was also found that as shown in Comparative Examples 5 to 7, thethermoplastic elastomers known to be useful for ordinary dampermaterials do not provide for the characteristics required of dampingmaterials for architectural viscoelastic dampers.

EXAMPLE 9

Using 50×50×5 mm sheets prepared from the composition of Example 5 and50 mm×100 mm×7 mm surface-treated steel sheets prepared by thesandblasting of general-purpose structural rolled steel sheets [SS400(JISG-3101)], the surfaces of which were coated with the adhesiveChemlock 487A/B (product of Lord Far East Incorporated) and dried atroom temperature for 1 hour, a small-sized viscoelastic damper wasfabricated by bonding together two of said damping sheets and three ofsaid steel sheets in the alternating manner illustrated in FIG. 1. Topromote curing of the adhesive, the damper was heated in an oven at 100°C. for 10 minutes and, then, left sitting at room temperature for 24hours. The viscoelastic damper thus completed was set with a jig on avibrating machine and a dynamic vibration test was carried out. MTS's831 Elastomer Test System was used as the tester and an incubator wasused for temperature control. The test conditions were: frequency 0.5Hz, strains 50%, 100% and 200%, temperatures 0° C., 10° C., 20° C., 30°C. and 40° C. The equivalent rigidity (Keq) and equivalent dampingfactor (heq) values calculated from the resulting hysteresis curves areshown in Table 2 and the hysteresis loops at 20° C. are shown in FIG. 2.

The equivalent damping factor (heq) is a value used for the dampingcapacity of a damper device for use in buildings. It is calculated fromthe hysteresis loops constructed by giving effective designdisplacements to a damping device. Thus, referring to FIG. 2, “heq” is avalue calculated by means of the following formula.heq=□W/2_(JI)Wwhere

-   W: the elastic energy of the damping device (unit: tf•m)-   □W: the rigidity of the energy absorbed by the damping device (the    area of the hysteresis loop shown in FIG. 2. Unit: tf•m)

Equivalent rigidity (Keq), which is an indicator of rigidity of thedamping material, is the gradient of a straight line drawn from theorigin to the (load, effective design displacement) shown in FIG. 2.

TABLE 2 Strain 50% 100% 200% Keq (0° C.) MPa 0.079 0.058 0.039 Keq (10°C.) MPa 0.043 0.034 0.026 Keq (20° C.) MPa 0.046 0.036 0.027 Keq (30°C.) MPa 0.037 0.030 0.023 Keq (40° C.) MPa 0.026 0.021 0.017 Keq (10°C.)/Keq (30° C.) — 1.2 1.2 1.1 Keq (0° C.)/Keq (40° C.) — 3.1 2.7 2.3heq (0° C.) — 0.38 0.48 0.57 heq (10° C.) — 0.41 0.47 0.51 heq (20° C.)— 0.40 0.46 0.51 heq (30° C.) — 0.40 0.45 0.48 heq (40° C.) — 0.36 0.400.43

It will be apparent from Table 2 that, in the actual measurement ofdamper performance, too, the viscoelastic damper fabricated from thecomposition of the invention is low in the temperature dependence ofrigidity and shows high damping capacities at and around roomtemperature. It can also be seen in FIG. 2 that the viscoelastic damperfabricated from the composition of the invention is an excellentarchitectural viscoelastic damper giving a hysteresis loop undergoing aconcentric expansion according to a varying strain and, therefore,having a small strain dependence (high linearity).

PRODUCTION EXAMPLE 3 TO 5 Production of Diblock Copolymers Comprising aPolystyrene Block and a Polyisobutylene Block

A 2 L reactor equipped with a stirrer was charged with 589 mL ofmethylcyclohexane (dried with molecular sieves in advance), 613 mL ofn-butyl chloride (dried with molecular sieves in advance) and 0.550 g ofcumyl chloride. After the reactor was cooled to −70° C., 0.35 mL ofα-picoline (2-methylpyridine) was added, further followed by addition ofisobutylene in the amount indicated in Table 3. Then, 9.4 mL of titaniumtetrachloride was added and the polymerization was thus started. Thereaction was carried out at −70° C. with constant stirring for 2.0hours. To this reaction mixture was added styrene in the amountindicated in Table 3, and the reaction was further continued for 60minutes, at the end of which time the reaction was stopped by adding alarge quantity of methanol. The solvent was removed from the reactionmixture and the polymer was dissolved in toluene and washed with 2portions of water. The toluene solution was poured in methanol toprecipitate the polymer, which was then dried in vacuo at 60° C. for 24hours to give a diblock copolymer comprising a polystyrene block and apolyisobutylene block (hereinafter referred to briefly as SIB-2 toSIB-4).

TABLE 3 Production Production Production Ex. 3 Ex. 4 Ex. 5 Diblockcopolymer SIB-2 STB-3 SIB-4 Isobutylene (g) 60.7 120.9 99.6 Styrene (g)11.1 21.9 42.6 Mn after 19100 35200 29900 polymerization of (1.05)(1.07) (1.07) isobutylene (Mw/Mn) Mn after 22700 42500 43100polymerization of (1.11) (1.17) (1.18) styrene (MW/Mn) Mn of polystyrene3600 7300 13200 block Styrene content 15 16 31 (wt %) of copolymer

PRODUCTION EXAMPLE 6 Production of a Triblock Copolymer Comprising aPolystyrene Block, a Polyisobutylene Block and a Polystyrene Block

A 2 L reactor equipped with a stirrer was charged with 570 mL ofmethylcyclohexane (dried with molecular sieves in advance), 590 mL ofn-butyl chloride (dried with molecular sieves in advance) and 0.400 g ofdicumyl chloride. After the reactor was cooled to −70° C., 0.34 mL ofα-picoline (2-methylpyridine) and 174 mL of isobutylene were added.Then, 10.3 mL of titanium tetrachloride was added and the polymerizationwas thus started. The reaction was carried out at −70° C. with constantstirring for 2.0 hours. To this reaction mixture was added 58 mL ofstyrene, and the reaction was further continued for 60 minutes, at theend of which time the reaction was stopped by adding a large quantity ofmethanol. The solvent was removed from the reaction mixture and thepolymer was dissolved in toluene and washed with 2 portions of water.The toluene solution was poured in methanol to precipitate the polymer,which was then dried in vacuo. at 60° C. for 24 hours to give a triblockcopolymer (hereinafter referred to briefly as SIBS-2).

In the SIBS-2 thus obtained, the number average molecular weight afterpolymerization of isobutylene was 69,000 (Mw/Mn=1.10), the numberaverage molecular weight after polymerization of styrene was 98,000(Mw/Mn=1.15), the molecular weight of the polystyrene block was 14,500,and the styrene content was 30 weight %.

EXAMPLES 10 TO 19 AND COMPARATIVE EXAMPLE 8

Using Labo-Plastomill (manufactured by Toyo Precision Machinery) set at170° C., the block copolymer (A) (SIB-2 to SIB-4 as produced inProduction Examples 3 to 5), thermoplastic elastomer, thermoplasticresin, tackifying resin and plasticizer were kneaded together accordingto the formulas shown in Table 4 for 15 minutes to give rubbercompositions. These rubber compositions were respectively press-moldedat 170° C. to manufacture sheets. From these sheets, specimens measuring6 mm L×5 mm W×2 mm T were cut out.

Using each specimen, the storage modulus G′ and loss tangent δ weremeasured with the dynamic viscoelasticity meter DVA-200 (IT MetricControl). The measuring frequency was 0.5 Hz.

The hot-melt properties of the above specimens were visually evaluatedat the temperatures indicated in Table 4. The evaluation criteria usedwere: ◯=sufficiently flowable on heating, □=moderately flowable, X=notflowable at all.

The results are shown in Table 4.

TABLE 4 Compar. Example Ex. 10 11 12 13 14 15 16 17 18 19 8 Formulation,Block copolymer (A) parts by SIB-2 80 — 80 — — — — — — — — weight SIB-3— 80 — 80 80 80 — — — — — SIB-4 — — — — — — 80 80 80 80 — Thermoplasticelastomer: SIBS-2 — — — — — — — — — — 100 SEPS 20 20 20 20 20 20 20 1020 20 — Thermoplastic resin: EOC — — — — 20 — — — 20 — — HDPE — — — — —20 — — — 20 — Tackifying resin: P-70 40 40 10 10 50 50 40 10 50 50 —P-100 — — — — — — — — — — 25 Plasticizer: PW-380 40 40 10 10 40 40 40 1040 40 — Performance Storage modulus 2.4 1.8 2.7 2.1 1.9 2.0 1.9 2.4 2.02.2 1.6 Evaluation ratio (G′_(10° C.)/G′_(30° C.)) Loss tangent (10° C.)0.64 0.42 0.90 0.51 0.51 0.53 0.45 0.70 0.56 0.58 0.59 (20° C.) 0.710.48 0.90 0.59 0.53 0.55 0.50 0.74 0.58 0.59 0.41 (30° C.) 0.70 0.560.76 0.67 0.58 0.61 0.56 0.75 0.60 0.62 0.31 Hot-melt properties (170°C.) ◯ ◯ ◯ Δ ◯ ◯ X X X X X (200° C.) ◯ ◯ ◯ Δ ◯ ◯ X X X X X (220° C.) ◯ ◯◯ ◯ ◯ ◯ X X X X X

The particulars of the thermoplastic elastomer, thermoplastic resin,tackifying resin and plasticizer mentioned in Table 4 are as follows.

-   Thermoplastic elastomer: SEPS (styrene-ethylene/propylene-styrene    triblock copolymer (SEPTON 2007, product of Kuraray)-   Thermoplastic resin: EOC (ethylene-octene copolymer (ENGAGE 8150,    product of Dow)-   Thermoplastic resin: HDPE (high-density polyethylene, HIZEX 2200J,    product of Mitsui Chemical)-   Tackifying resin: P-70 (ARCON P-70, product of Arakawa Chemical)-   Tackifying resin: P-100 (ARCON P-100, product of Arakawa Chemical)-   Plasticizer: PW-380 (paraffinic process oil PW-380, product of    Idemitsu Kosan)

Examples 10 to 19 were invariably satisfactory in the balance betweendamping capacity and temperature-dependence of rigidity at and aroundroom temperature. Particularly in comparison with Examples 16 and 17,Examples 10 to 13 showed selective improvements in hot-melt propertiessubstantially without being affected in dynamic characteristics, i.e.the balance between tan δ and temperature-dependence of G′. Moreover, inExamples 14 and 15 where in EOC or HDPE was formulated, hot-meltproperties were selectively improved substantially without compromise indynamic characteristics, namely the balance between tan δ and thetemperature dependence of G′.

EXAMPLE 20

Damper material compositions were produced according to the formulasindicated in Table 5 in otherwise the same manner as in Examples 10 to19. From each composition thus obtained, a 12 g aliquot was weighed outand sandwiched between 50 mm×100 mm×7 mm general-purpose structuralrolled steel [SS400 (JISG-3101)] sheets sandblasted for surfacetreatment in advance. The assembly was heated in an oven at 190° C. tocause the composition to flow, whereby a small-sized viscoelastic damperof the shape illustrated in FIG. 1 was obtained. The composition becamesufficiently flowable at 190° C. and was found to show sufficientadhesion to steel sheets without leaving air cells, thus havingsatisfactory hot-melt processability.

TABLE 5 Ex. 20 Formulation, parts by weight Block copolymer (A): SIB-2 —SIB-3 80 SIB-4 — Thermoplastic elastomer: SIBS-2 — SEPS 10 10Thermoplastic resin: EOC 20 HDPE — Tackifying resin: P-70 50 P-100Plasticizer: PW-380 40 Performance evaluation Storage modulus ratio 2.2(G′ _(10° C.)/G′ _(30° C.)) Loss tangent (10 ° C.) 0.55 (20 ° C.) 0.63(30 ° C.) 0.76 Hot-melt properties (170° C.) ◯ (200° C.) ◯ (220° C.) ◯

The viscoelastic damper obtained was set with a jig on a vibratingmachine and a dynamic vibration test was carried out. MTS's 831Elastomer Test System was used as the testing instrument and anincubator was used for temperature control. The measuring conditionswere: frequency 0.5 Hz, strain 50%, 100% or 200%; temperature 0° C., 10°C., 20° C., 30° C. or 40° C. The equivalent rigidity (Keq) andequivalent damping factor (heq) values calculated from the hysteresisloops are shown in Table 6. The hysteresis loops at 20° C. are shown inFIG. 3.

TABLE 6 Strain 50% 100% 200% Keq (0° C.) MPa 0.161 0.121 0.075 Keq (10°C.) MPa 0.121 0.085 0.053 Keq (20° C.) MPa 0.081 0.057 0.037 Keq (30°C.) MPa 0.062 0.045 0.032 Keq (40° C.) Mpa 0.041 0.032 0.026 Keq (10°C.)/Keq (30° C.) — 2.0 1.9 1.7 Keq (0° C.)/Keq (40° C.) — 3.9 3.8 2.9heq (0° C.) — 0.35 0.45 0.61 heq (10° C.) — 0.36 0.47 0.63 heq (20° C.)— 0.41 0.53 0.64 heq (30° C.) — 0.46 0.56 0.61 heq (40° C.) — 0.48 0.550.56

It will be apparent from Table 6 that, in the actual measurement ofdamper performance, the viscoelastic damper fabricated using the dampermaterial composition of this invention is low in the temperaturedependence of rigidity and shows a high damping capacity at and aroundroom temperature. It can also seen in FIG. 3 that the viscoelasticdamper fabricated using the damper material composition of thisinvention shows a concentric expansion of its hysteresis loop accordingto an increasing strain, thus being an excellent architecturalviscoelastic damper with a small strain dependence (high linearity).Moreover, no delamination from steel sheets was observed even under alarge strain of 200%, indicating that the composition shows sufficientadhesion.

EXAMPLE 21

Using the damper material composition produced in Example 20, adouble-sided self-adhesive tape was fabricated by means of asingle-screw extruder. The screw temperature was set at 90° C. and thedie temperature was set at 110° C. The thickness and width of the tapewere controlled at 1 mm and 50 mm, respectively.

The adhesion of the product tape was evaluated by a shear test. The tapewas cut to 25 mm×25 mm and secured to one edge of a sandblasted 25mm×100 mm×5 mm general-purpose structural steel sheet [SS400 (JISG-3101)]. Then, another steel sheet was secured to the tape to prepare aspecimen for the shear test. Using Autograph AG-10TB (ShimadzuCorporation), the specimen was pulled in the shear direction at a speedof 300 mm/min and the maximum strain causing detachment or destructionof the tape was measured. As a result, the maximum strain was found tobe 2280%. The destruction was a cohesive failure and no interfacialfailure took place. The above findings indicate that the damper materialcomposition according to the present invention enables the provision ofa double-sided self-adhesive tape having sufficient adhesion and capableof functioning as a double-sided self-adhesive tape havingvibration-damping properties.

INDUSTRIAL APPLICABILITY

The damper material composition of the present invention not onlyfeatures an improvement in the attenuation of damping capacity at 20 to40° C. and a consequent good balance between damping capacity andtemperature dependence of rigidity at and around room temperature, whichare conflicting characteristic parameters, but also self-adhesiveproperties and good deformability, thus enabling the provision ofexcellent architectural viscoelastic dampers.

Furthermore, the damper material composition of the invention hasexcellent hot-melt processability in addition to the good balancebetween damping capacity and temperature dependence of rigidity at andaround room temperature, thus enabling the provision of an architecturaldamper and a vibration-damping double-sided self-adhesive tape, both ofwhich have excellent hot-melt processability.

1. A damper material composition which comprises: a block copolymer (A)comprising a polymer block (a) and polymer block (b) and terminating insaid polymer block (b); wherein said polymer block (a) is comprised ofan aromatic vinyl compound as a constituent monomer and said polymerblock (b) is comprised of isobutylene as a constituent monomer; andwherein the ratio of the storage modulus (G′) value at 0° C. to thecorresponding value at 40° C. as found by the measurement of dynamicviscoelasticity at a frequency of 0.5 Hz and a shear strain of 0.05% inthe shear mode, namely (G′_(0° C.)/G′_(40° C.)), is not greater than 10,and the loss tangent (tan δ) value as found by said measurement is notsmaller than 0.4 at 0° C. to 40° C.; and wherein the aromatic vinylcompound is at least one selected from the group consisting of styrene,o-, m- or p-methylstyrene, β-methylstyrene, 2,6-dimethylstyrene,2,4-dimethylstyrene, α-methyl-o-methylstyrene, α-methyl-m-methylstyrene,α-methyl-p-methylstyrene, β-methyl-o-methylstyrene,β-methyl-m-methylstyrene, β-methyl-p-methylstyrene, 2, 4,6-trimethylstyrene, α-methyl-2, 6-dimethylstyrene, α-methyl-2,4-dimethylstyrene, β-methyl-2, 6-dimethylstyrene, β-methyl-2,4-dimethylstyrene, o-, m- or p-chlorostyrene, 2,6-dichlorostyrene,2,4-dichlorostyrene, α-chloro-o-chlorostyrene, α-chloro-m-chlorostyrene,α-chloro-p-chlorostyrene, β-chloro-o-chlorostyrene,β-chloro-m-chlorostyrene, β-chloro-p-chlorostyrene,2,4,6-trichlorostyrene, α-chloro-2, 6-dichlorostyrene, α-chloro-2,4-dichlorostyrene, β-chloro-2,6-dichlorostyrene, β-chloro-2,4-dichlorostyrene, o-, m- or p-t-butylstyrene, o-, m- orp-methoxystyrene, o-, m- or p-chloromethylstyrene, o-, m- orp-bromomethylstyrene, silyl-substituted styrene derivatives, indene andvinylnaphthalene.
 2. The damper material composition according to claim1 wherein the block copolymer (A) is a diblock copolymer having apolymer block (a)—polymer block (b) structure.
 3. The damper materialcomposition according claim 2 wherein the polymer block (a) has a numberaverage molecular weight of not more than 10,000.
 4. The damper materialcomposition according to any of claims 1, 2 or 3 containing at least onekind of a tackifying resin and a plasticizer.
 5. The damper materialcomposition according to claim 1 containing at least one kind ofthermoplastic resin (C).
 6. A damper material composition whichcomprises: a block copolymer (A) comprising a polymer block (a) and apolymer block (b) and terminating in said polymer block (b), and athermoplastic resin (C); wherein said polymer block (a) is comprised ofan aromatic vinyl compound as a constituent monomer and said polymerblock (b) is comprised of isobutylene as a constituent monomer; whereinthe ratio of the storage modulus (G′) value at 0° C. to thecorresponding value at 40° C. as found by the measurement of dynamicviscoelasticity at a frequency of 0.5 Hz and a shear strain of 0.05% inthe shear mode, namely(G′_(0° C.)/G′_(40° C.)), is not greater than 10,and the loss tangent (tan δ) value as found by said measurement is notsmaller than 0.4 at 0° C. to 40° C.; and wherein the thermoplastic resin(C) is at least one selected from the group consisting ofethylene-propylene copolymer, ethylene-butene copolymer, ethylene-hexenecopolymer, ethylene-octene copolymer, ethylene-vinyl acetate copolymer,ethylene-ethyl acrylate copolymer, high-density polyethylene,low-density polyethylene, linear low-density polyethylene andisobutylene-isoprene copolymer (butyl rubber).
 7. The damper materialcomposition according to claim 1 containing at least one kind ofthermoplastic elastomer (D).
 8. The damper material compositionaccording to claim 7 wherein the thermoplastic elastomer (D) is at leastone selected from the group consisting of a triblock copolymer havingthe structure of (a polymer block comprised of an aromatic vinylcompound as a constituent monomer)—(a polymer block comprising aconjugated diene as a constituent monomer and optionallyhydrogenated)—(a polymer block comprised of an aromatic vinyl compoundas a constituent monomer) and a triblock copolymer having the structureof (a polymer block comprised of an aromatic vinyl compound as aconstituent monomer)—(a polymer block comprised of isobutylene as aconstituent monomer)—(a polymer block comprised of an aromatic vinylcompound as a constituent monomer).
 9. A damper material compositioncomprising: a diblock copolymer (A′) comprising a polymer block (a′) anda polymer block (b); said polymer block (a′) being comprised of anaromatic vinyl compound as a constituent monomer and having a numberaverage molecular weight of not more than 10,000; and said polymer block(b) being comprised of isobutylene as a constituent monomer; wherein theratio of the storage modulus (G′) value at 10° C. to the correspondingvalue at 30° C. as found by the measurement of dynamic viscoelasticityat a frequency of 0.5 Hz and a shear strain of 0.05% in the shear mode,namely (G′_(10° C.)/G′_(30° C.)), is not greater than 2, and the losstangent (tan δ) value as found by said measurement is not smaller than0.4 at 10° C. to 30° C.; and wherein the aromatic vinyl compound is atleast one selected from the group consisting of styrene, o-, m- orp-methylstyrene, β-methylstyrene, 2,6-dimethylstyrene,2,4-dimethylstyrene, α-methyl-o-methylstyrene, α-methyl-m-methylstyrene,α-methyl-p-methylstyrene, β-methyl-o-methylstyrene,β-methyl-m-methylstyrene, β-methyl-p-methylstyrene, 2, 4,6-trimethylstyrene, α-methyl-2, 6-dimethylstyrene, α-methyl-2,4-dimethylstyrene, β-methyl-2, 6-dimethylstyrene, β-methyl-2,4-dimethylstyrene, o-, m- or p-chlorostyrene, 2,6-dichlorostyrene,2,4-dichlorostyrene, α-chloro-o-chlorostyrene, α-chloro-m-chlorostyrene,α-chloro-p-chlorostyrene, β-chloro-o-chlorostyrene,β-chloro-m-chlorostyrene, β-chloro-p-chlorostyrene,2,4,6-trichlorostyrene, α-chloro-2, 6-dichlorostyrene, α-chloro-2,4-dichlorostyrene, β-chloro-2,6-dichlorostyrene, β-chloro-2,4-dichlorostyrene, o-, m- or p-t-butylstyrene, o-, m- orp-methoxystyrene, o-, m- or p-chloromethylstyrene, o-, m- orp-bromomethylstyrene, silyl-substituted styrene derivatives, indene andvinylnaphthalene.
 10. The damper material composition according to claim9 containing at least one kind of thermoplastic elastomer (D).
 11. Thedamper material composition according to claim 10 wherein thethermoplastic elastomer (D) is a triblock copolymer having the structureof (a polymer block comprised of an aromatic vinyl compound as aconstituent monomer)—(a polymer block comprised of a conjugated diene asa constituent monomer and optionally hydrogenated)—(a polymer blockcomprised of an aromatic vinyl compound as a constituent monomer).
 12. Adamper material composition comprising: a diblock copolymer (A′)comprising a polymer block (a′) and a polymer block (b), and athermoplastic resin (C); said polymer block (a′) being comprised of anaromatic vinyl compound as a constituent monomer and having a numberaverage molecular weight of not more than 10,000; and said polymer block(b) being comprised of isobutylene as a constituent monomer; wherein insaid damper material the ratio of the storage modulus (G′) value at 10°C. to the corresponding value at 30° C. as found by the measurement ofdynamic viscoelasticity at a frequency of 0.5 Hz and a shear strain of0.05% in the shear mode, namely (G′_(10 ° C.)/G′_(30 ° C.)), is notgreater than 2, and the loss tangent (tan δ) value as found by saidmeasurement is not smaller than 0.4 at 10° C. to 30° C.; and wherein thethermoplastic resin (C) is at least one selected from the groupconsisting of ethylene-propylene copolymer, ethylene-butene copolymer,ethylene-hexene copolymer, ethylene-octene copolymer, ethylene-vinylacetate copolymer, ethylene-ethyl acrylate copolymer, high-densitypolyethylene, low-density polyethylene, linear low-density polyethyleneand isobutylene-isoprene copolymer (butyl rubber).
 13. The dampermaterial composition according to claim 9 containing at least one kindof a tackifying resin and a plasticizer.
 14. The vibration damper havingthe structure of a combination of the damper material compositionaccording to claim 1, 6, 9 or 12 with steel sheet or steel pipe.
 15. Adamping double-sided self-adhesive tape comprising the damper materialcomposition according to claim 1, 6, 9 or 13 as molded in the form of atape.
 16. The damper material composition according to claim 1 or 9,wherein the aromatic vinyl compound is at least one selected from thegroup consisting of styrene, p-methylstyrene, p-chlorostyrene,p-t-butylstyrene, p-methoxystyrene, p-chloromethylstyrene,p-bromomethylstyrene, silyl-substituted styrene derivatives and indene.17. The damper material composition according to claim 16, wherein thearomatic vinyl compound is at least one selected from the groupconsisting of styrene, p-methylstyrene and indene.
 18. The dampermaterial composition according to claim 17, wherein the aromatic vinylcompound is styrene.
 19. The damper material composition according toclaim 10, containing at least one kind of thermoplastic resin (C).